Twin-mediated epitaxial growth of highly lattice-mismatched Cu/Ag core–shell nanowires

Abstract

Lattice-mismatch is an important factor for the heteroepitaxial growth of core-shell nanostructures. A large lattice-mismatch usually leads to a non-coherent interface or a polycrystalline shell layer. In this study, a conformal Ag layer is coated on Cu nanowires with dense nanoscale twin boundaries through a galvanic replacement reaction. Despite a large lattice mismatch between Ag and Cu (∼12.6%), the Ag shell replicates the twinning structure in Cu nanowires and grows epitaxially on the nanotwinned Cu nanowire. A twin-mediated growth mechanism is proposed to explain the epitaxy of high lattice-mismatch bimetallic systems in which the misfit dislocations are accommodated by coherent twin boundaries.

Investigation on Stranski–Krastanow (SK) Growth Mode of Ag Coating in Cu/Ag Core-Shell Composites

“…(The background value of the epoxy resin has been removed). The above characterization results are similar to those in the literature, proving that the material synthesis is successful [13].…”

“…(The background value of the epoxy resin has been removed). The above characterization results are similar to those in the literature, proving that the material synthesis is successful [13]. For low-dimensional Cu/Ag core-shell structures, there are three heteroepitaxial growth modes of Ag coating, namely the Frank-Van der Merwe (FM) mode, the Volmer-Weber (VW) mode, and Stranski-Krastanow (SK) mode.…”

“…In core-shell composites, the HRTEM images of the interface were used to investigate the deposition of the coating. It is reported that the growth of Ag coating on Cu nanowires confirms to heteroepitaxial growth, and the Ag shell retains the same crystallographic orientation and twin structure as Cu nanowires [13]. However, for spherical particles, the growth mode of shell and the relationship between the substrate and the coating are not clear.…”

Copper–Silver Bimetallic Nanowire Arrays for Electrochemical Reduction of Carbon Dioxide

“…The morphologies of these Cu–Ag NWs were similar to the Cu NWs (i.e., diameter of ~100 nm with length of up to 30 μm), despite some deposition on the surface of the Cu NWs. The rough surface could be ascribed to the large lattice mismatch between Cu and Ag [36]. To verify the crystal structure of Cu–Ag NWs, power XRD measurement was performed.…”

Nanowire Genome: A Magic Toolbox for 1D Nanostructures

“…Clearly, the galvanic reaction quickly took place between Ag + and Cu NWs, which resulted in Ag nanosheets deposited onto Cu NWs (Figure d) . Moreover, the galvanic replacement of Cu by Ag + could be suppressed by adding a high concentration of the reducing agent (such as ascorbic acid) . The resultant Cu–Ag NWs showed an increased shell thickness of 14 nm with less etching of the Cu core (Figure e).…”